If you use GitHub, then ZenHub is a great option. It is a Chrome extension which adds project management functionality inside the GitHub interface.
Disclosure: I work at ZenHub - the favourite feedback I get is how much it cuts down on context switching between where developers want to live - GitHub, and where Project Managers want to live Jira/Trello/etc, as everyone can work directly from GitHub Issues.
Disclosure: I work at ZenHub - the favourite feedback I get is how much it cuts down on context switching between where developers want to live - GitHub, and where Project Managers want to live Jira/Trello/etc, as everyone can work directly from GitHub Issues.
https://www.zenhub.io/